The studies proposed in this grant application exemplify a continuation o( our ongoing studies on the involvement of papillomaviruses in the development of epithelium-derived benign and malignant tumors. While we intend to continue to explore the epidemiological relationships regarding the presence of papillomavirus genomes in various human and animal tumors which have not yet been analyzed, the overall goal of our studies is to delineate the mechanism by which papillomavirus-induced benign tumors progress to the malignant phenotype. The two systems that we have chosen for these analysis include the human chronic wart disease syndrome epidermodysplasia verruciformis (EV), and the rabbit model wart disease syndrome induced by cottontail rabbit papillomavirus (CRPV). Both of these syndromes are related cutaneous wart diseases exhibiting a high rate of malignant progression and an unequivocal association with papillomavirus DNA. Specifically our renewal application proposes to: 1) continue our survey of human and animal preneoplastic, hyperplastic, and proliferative papilloma-like lesions and associated cancers for the presence, type, and physical state of papillomavirus DNA. These studies will include epidemiological and natural history studies on histologically-defined tumors and unusual cutaneous lesions in humans as well as a variety of benign and malignant tumors in monkeys that contain novel species of papillomaviruses which we have recently identified: and 2) analyze papillomavirus-infected normal, benign, malignant, and metastatic tissues from rabbits infected with CRPV and patients with EV in an effort to determine the nature, structure and physical state of the viral genome during the progression of benign tumors to the malignant phenotype. In these studies we will attempt to identify any viral or cell- specific sequences that may contribute to malignant progression or are expressed as a consequence of this phenomenon. This will be accomplished by analyzing cDNA libraries for unique viral and cell- specific nucleotide sequences by a variety of methods including subtractive hybridization. Ultimately, we propose to identify and characterize the proteins that are coded specific for by these specific nucleotide sequences. The methodologies that we plan to employ to achieve these objectives are for the most part already implemented in our laboratory and include a variety of physicochemical, enzymological and filter hybridization techniques available for the analysis of DNA, RNA, and proteins.